1. Field of the Invention
The present invention relates to a low pressure plasma exciting single-wafer type thin film deposition apparatus used in the fabrication of semiconductors or liquid crystal displays to deposit a thin film over a water or substrate, and more particularly to a single-wafer type thin film deposition apparatus which includes a mesh type radio frequency (RF) electrode plate adapted to form plasma, a baffle guide adapted to prevent the plasma from diffusing at a low pressure, and a control unit adapted to prevent a reacted raw material from generating a degraded reaction in a gas injector.
2. Description of the Prior Art
Various thin film deposition devices are known. Conventional thin film deposition devices are mainly classified by those in which deposition of a thin film is carried out at high temperature and low pressure and those in which deposition of a thin film is carried out using excited plasma.
In the case of thin film deposition devices in which deposition of a thin film is carried cut at high temperature and low pressure, it is difficult to obtain a thin film with a desired composition, particularly, when a multi-element reacting raw material is used. This is because the reacting energy gap among the elements of the reacting raw materials increases. Furthermore, there is a considerable limitation on the process range for forming thin films.
On the other hand, in the case of thin film deposition devices using excited plasma, deposition of a thin film may be conducted on an unnecessary area when it is carried out at low pressure. This is because plasma diffuses at low pressure. Furthermore, an incomplete thin film may be formed on the area in the vicinity of the gas injector which injects the reacting raw material, thereby resulting in the formation of particles. Also, a problem is that when a thin firm is deposited over micro patterns, its coverage becomes non-uniform because of a self-bias effect of plasma.